Let \(G\)  be a graph. An unordered triple \(\lbrace x,y,z\rbrace  \subseteq V(G)\) 
is \(G\) -odd if \(|E(G[\lbrace x,y,z\rbrace ])|\)  is odd.
We denote by \(co(G)\)  the 3-uniform hypergraph with
vertex set \(V(G)\)  and such that
\(\lbrace x,y,z \rbrace  \in E(co(G))\)  if and only \(\lbrace x,y,z\rbrace \)  is \(G\) -odd.
Hypergraphs in \(co(G)\)  are called 3-cocycles or two-graphs ([1]}).
Note that every cocyle and every complement of a cocycle is
clique friendly. Moreover, by (REF ) doubly perfect 3-uniform
hypergraphs are cocycles.
